Original Article Changes in Exercise-Induced Gene Expression in 5-AMP–Activated Protein Kinase 3–Null and 3 R225Q Transgenic

5-AMP–activated protein kinase (AMPK) is important for metabolic sensing. We used AMPK3 mutant–overexpress-ing Tg-Prkag3225Q and AMPK3-knockout Prkag3/ mice to determine the role of the AMPK3 isoform in exercise-induced metabolic and gene regulatory responses in skele-tal muscle. Mice were studied after 2 h swimming or 2.5 h recovery. Exercise increased basal and insulin-stimulated glucose transport, with similar responses among geno-types. In Tg-Prkag3225Q mice, acetyl-CoA carboxylase (ACC) phosphorylation was increased and triglyceride con-tent was reduced after exercise, suggesting that this muta-tion promotes greater reliance on lipid oxidation. In contrast, ACC phosphorylation and triglyceride content was similar between wild-type and Prkag3/ mice. Ex-pression of genes involved in lipid and glucose metabolis